Clamping devices exist in many different forms and are used in a wide variety of applications. Further, clamping devices that retain a centrally elongate inserted member, such as a rope or rod, and applying an amount of friction to the inserted member, so as to either securely retain the inserted member--which is in essence a static clamping device--or permit controlled relative movement of the inserted member with respect to the clamping device--which is in essence a dynamic clamping device--are known in many different forms.
One example of a use of such a static clamping device is a workpiece clamping device wherein an object, such as an elongate metal or plastic pipe, could be firmly retained for working on. Most presently available clamping devices, such as a vice, utilize opposed clamping members made from a rigid material and, therefore, tend to mark or in some way disfigure the outer surface of a retained workpiece. What is needed is a static clamping device wherein a relatively soft gripping member applies generally even pressure around an object in order to grip that object, even grip the object tightly, without causing damage to the outer surface of the object.
Further, clamping devices for very gently clamping objects, with a selective and entirely controlled pressure, are generally not known. For example, when a person has fractured a bone in an appendage, an arm for instance, it would be useful to gently restrain the arm in a proper position until a conventional east or the like can be applied. Such gentle restraint of the arm could be accomplished by applying a pressure that is gentle, selectively controllable, and that is relatively evenly distributed around the arm and along the length of the arm.
Various applications require that a clamping device be used in a dynamic situation where the inserted workpiece, such as a rope, is purposely drawn through the clamping device--or the clamping device is drawn along the inserted member--so as to provide a frictional interface between the clamping device and the inserted member. One example of a dynamic clamping device is cable type exercise equipment. Various types of friction based dynamic clamping type cable exercise devices exist--it is beyond the scope of the present application to explain these devices in detail. Basically, a cable or rope is frictionally engaged by a selectively tightenable clamping means. The problem with such prior art exercise devices is that the amount of frictional force is constant for any given setting. Therefore, in use, pulling on the cable or rope with a greater force will result in the cable or rope being pulled through the clamping mechanism at a greater speed. This may be undesirable as it is very often desirable to control the rate of relative speed of the clamping mechanism and the cable.
Another use for a dynamic clamping device is an emergency fire escape where a harness or similar apparatus having one or more clamping mechanisms installed thereon frictionally engages a rope hanging down the exterior of a building so as to permit the harness or similar to, in essence, slide down the rope in a controlled manner at a pre-selected speed. Such emergency fire escapes would allow for the escape down the exterior of a building that perhaps has a couple of interior stairways that are unusable due to fire or smoke.